Path: utzoo!utgpu!attcan!uunet!lll-winken!lll-lcc!ames!haven!uvaarpa!babbage!mac3n
From: mac3n@babbage.acc.virginia.edu (Alex Colvin)
Newsgroups: comp.dcom.lans
Subject: Re: Token Ring (was: Re: Info on LANs)
Message-ID: <486@babbage.acc.virginia.edu>
Date: 6 Jan 89 14:29:59 GMT
References: <5777@medusa.cs.purdue.edu>
Organization: University of Virginia
Lines: 22

> Proteon (like most Ethernet vendors) botched their ring hardware in
> its packet buffering capability.  The ProNET-10 that we have (both
> UNIBUS and Q-Bus versions) can't handle back-to-back packets.  The

You're right there.  Your driver has to get the packet off the board as fast
as it possibly can.  By the way, I believe the VME bus version has several
receive buffers.

Personally, if I get a REFUSED (not copied), I usually do an immediate
transmit (after DMA).  That usually finds the receiver ready.
802.5's copied bit would be slightly better.

I heard that the new IBM 16 Mb/s TRN card for the PC has 64K on-board buffer
instead of the old 4K.  No matter what you've got, for sustained bulk transfer
you have to match the transfer rates across the system busses.

Another thought:  I'd like to get a receive interrupt when the packet starts
arriving, not when it's completed.  That would let me get an early start.
By the time i get into the interrupt handler the header would be ready.
More overlap.

			-- happy trailers...